In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed.
For example, transmission schemes and reception schemes based on the use of narrow beams might be needed at high frequencies to compensate for propagation losses. For a given communication link, a beam can be applied at both the network side (such as at the transmission and reception point (TRP) of a network node) and the user side (such as at wireless devices served by the network node). A beam pair link (BPL) is defined by the beam used by the TRP (denoted TRP beam) for communicating with the wireless device and the beam used by the wireless device (denoted WD beam) for communicating with the TRP. Each of the TRP beam and the WD beam could be used for any of transmission and reception. Likewise, there could be separate BPLs for downlink communications (where the TRP beam is a transmission (TX) beam and where the WD beam is a reception (RX) beam) and uplink communications (where the TRP beam is an RX beam and where the WD beam is a TX beam).
Beam training is generally performed for each TRP TX beam, using the corresponding reference signals, in order to find suitable WD RX beams. During this WD RX beam training the wireless device finds a best WD RX beam based on received RS power or some other metric when measuring on a RS transmitted in a TRP TX beam.
The wireless devices and/or the TRP of the network node could implement beamforming by means of analog beamforming, digital beamforming, or hybrid beamforming. Each implementation has its advantages and disadvantages. A digital beamforming implementation is the most flexible implementation of the three but also the costliest due to the large number of required radio chains and baseband chains. An analog beamforming implementation is the least flexible but cheaper to manufacture due to a reduced number of radio chains and baseband chains compared to the digital beamforming implementation. A hybrid beamforming implementation is a compromise between the analog and the digital beamforming implementations. As the skilled person understands, depending on cost and performance requirements of different wireless devices, different implementations will be needed.
In some situations the interference experienced at a wireless device will be bursty. This might be due to the use of narrow beams with high gains that might be used at high frequencies. With such high gain transmissions, an interfering beam from a non-serving TRP can cause a large degradation in signal to interference plus noise ratio (SINR). Another reason could be the use of dynamic time division duplexing (TDD), where the downlink and uplink time slots can vary individually per served wireless device. This means that for two wireless devices geographically located close to each other, one wireless device could have an uplink time slot and transmitting data while the other wireless device has a downlink time slot and hence receives data. This can lead to significant interference experienced by the receiving wireless device from the transmitting wireless device.
If a wireless device detects a sudden strong interference during reception for an initial WD RX beam, a temporary switch to another WD RX beam might improve the interference situation. However, if there is analog beamforming in the wireless device it might take too long time to search for a good alternative WD RX beam using the above disclosed beam training, which might further degrade the performance.
Hence, there is still a need for an improved handling of interference at a receiving radio transceiver device.